LAUGHTON
ELECTRONICS

PLC interfaces
with existing automation
to drive two process
conveyors

In my client's
experimental recycling
operation, batches of rubber pass through an
automated
grinder (right) then, via conveyor, to the refiner mill at left. After
a specified period in the refiner the batch is discharged by reversing
the direction of a second conveyor. Originally it was the machine
operator's responsibility to wait for the grinder to unload,
then engage
conveyor 1 to load the refiner. After the process delay
(timed manually) s/he would unload the refiner by
temporarily reversing
conveyor 2.

Automating the
conveyors makes the batches more consistent
since the process delay is not subject to human error. Automation
also makes the operator's job easier.

I selected an Omega
Engineering
HE-XE102 PLC to run the show. With this unit
the HMI is included, and
virtual controls on the LCD graphics screen relieve the need for
hardware switches and indicators.
The program I provided makes all process variables easily alterable
(though protected by password),
and a diagnostic screen displays the status of inputs and outputs
during setup and troubleshooting.